Testosterone is often called the male hormone and plays a role in muscle development. However, it also naturally occurs in females. Athletes are interested in testosterone to increase muscle mass and recovery. Therefore, some choose to inject testosterone to increase the testosterone levels in their body, also known as 'taking steroids'.

Testosterone injections effectively increase muscle mass gains in combination with resistance training. However, this study found that injecting testosterone even increased muscle mass when subjects did not train at all!

While injecting high doses of testosterone is very effective in increasing muscle mass gains, small differences in your natural testosterone levels do not matter that much as long as you're in a healthy range (1). For example, muscle mass gains are similar in males, despite lower testosterone levels in females (2).

There is a small increase in testosterone after your workout. However, this increase is very small and short, and doesn't contribute much to your gains (3).

There are a lot of supplements which claim to boost your bodies natural production of testosterone.

However, there is little to no evidence that supports that such supplements can improve your gains.

The authors state explicitly that their results are in no way a justification for the use of anabolic steroids, which can have serious side effects.

Key PointsSarcoplasmic hypertrophy – growth of the sarcoplasm that outpaces the growth of the myofibrils – does seem to happen to a significant degree.Simple increases in glycogen storage don’t seem to be the primary driver of sarcoplasmic hypertrophy. It seems to be driven by an increase in sarcoplasmic protein content.The degree to which sarcoplasmic hypertrophy takes place may be influenced by training, but whether you can specifically train for sarcoplasmic vs. myofibrillar hypertrophy is unclear. More than anything, it seems to be a natural consequence of muscle growth itself.Looking at strength differences between bodybuilders and powerlifters or weightlifters is not a valid way to assess degree of sarcoplasmic hypertrophy. However, dismissing sarcoplasmic hypertrophy simply because there are better explanations for the observed differences in relative strength is foolhardy.It’s unclear whether steroids increase the amount of sarcoplasmic hypertrophy that takes place.

You may have heard the old piece of bodybuilding forum “wisdom”: “Bodybuilders are bigger than powerlifters/weightlifters but still lift less because they have more sarcoplasmic hypertrophy, bro.”

"Furthermore, a study by Moore et al found that while protein consumptions affects both myofibrillar and sarcoplasmic protein synthesis, strength training (10 sets with 8-10rm loads) only affects myofibrillar protein synthesis. However, the question of training style remains: the sarcoplasmic protein synthesis response may have been different with a different training intervention.

Finally (and unrelatedly), this is a good study to share with people who claim that creatine only causes muscle growth via an increase in water content in the muscle (i.e. sarcoplasmic hypertrophy). The groups taking creatine in this study had the largest increase in contractile protein content; even if water content increased, that increase was outpaced by the observed increases in contractile protein content.

Addendum, January 2018A recent meta-analysis by Schoenfeld et al looking at the effects of training load on hypertrophy, dynamic strength, and isometric strength helps counter one of the main arguments people use to contend that light, high rep training causes sarcoplasmic hypertrophy. People claim that since strength gains are larger with heavier training, heavy training must be adding more contractile proteins (myofibrillar hypertrophy), while lighter training must be expanding muscle size without adding as many contractile proteins (sarcoplasmic hypertrophy). Earlier in this article I discussed why that’s not an entirely logical argument, but this meta-analysis provides us with some direct evidence to refute it.

Unsurprisingly, heavy training was better for dynamic strength. However, there’s a skill component to dynamic strength, and heavier training helps to train that skill. On the other hand, there was no significant difference between high load and low load training for gains in isometric strength (i.e. force output with virtually no skill required). This suggests that low load training is still adding contractile proteins just as effectively as high load training; it’s just not great for training you to use them effectively for maximal dynamic contractions (i.e. 1RMs).

This meta-analysis was discussed in more detail in Volume 1, Issue 7 of MASS."

Supplement companies are constantly pushing mTOR as the magic pathway to building muscle, and various net guru type talk about keeping mTOR activated, with heavy marketing of Leucine, BCAA, etc. to keep mTOR activated. It’s unlikely that keeping an anabolic pathway such as mTOR active is a path to longevity. It’s interesting to note, cancer researchers, anti aging researchers, etc are looking for ways to limit/control mTOR.

I listen to very well known plant-based athlete's podcast, and the host often has guests on who warn listeners of the dangers of eating animal foods due to their high leucine content.

Leucine is one of the building-block amino acids of proteins, and found in much higher amounts in animal protein sources than plant protein sources.

The often touted fear of consuming leucine, is that leucine works as a primary signalling molecule to drive a cascade of processes for cell growth (mTOR pathway). So the thought is, that consuming this amino acid in high amounts will needlessy grow harmful cells increasing the risk of tumors and cancer.

Numerous studies have shown that whole animal protein sources (eggs, meat, diary) are more "anabolic" (growth promoting) for muscle tissue than plant protein sources. Which is also the reason why supplemental plant based isolated protein powders (hemp, pea, soy, etc) are fortified with leucine because they lack it naturally.

Now I have no problem agreeing that chronically driving anabolic processes in the body are not helpful. Certainly I would not recommend a high-protein diet to a sedentary individual who is also consuming an excess of food daily. Quite simply they are asking the body to grow without much need for growth. The same way I would not recommend someone drink sports drinks and sit on the couch all day. It's a case of need.

However, we know that one of the biggest risk factors for woman particulary in later life is loss of mobility and ability to function in old age. This is due to the rate of loss of muscle as we age, and that women in general have less muscle mass compared to men by default. It is a compounding effect.

I want to share a quote from research paper I just came across:

"We showed that the addition of leucine to a mixed-protein beverage containing 15g high-quality protein and a total of 4.2 g leucine/serving (∼1.1 g inherent and ∼3.1 g exogenous) enhanced the myoPS response to feeding compared with ingestion of an isoenergetic, isonitrogenous beverage containing ∼1.3 g leucine. We also showed that both the LEU and CON beverages increased acute myoPS rates above fasted levels in older women, with the increase being greater in a leg that performed resistance exercise. Importantly, the acute myoPS response was greater following LEU than CON in both the rested and exercised state."

Let me break that down:

The researchers added ~3.1g of leucine to a mixed protein beverage containing 15g of protein (~1.1g of leucine inherently). This beverage was given to older women who also resistance trained one leg.

The results of the experiment were that the women who consumed the beverage above, showed greater rates of muscle protein synthesis (myoPS), with the increases being greatest in the trained leg.

Also the women consuming the beverage showed greater indicators of muscle growth, than women who consumed a protein beverage without the added leucine, or no protein beverage at all.

Right, so what we know...

As we age we lose muscle.

Resistance training stimulates muscle growth.

Adequate leucine per meal (~3g) turns on muscle growth, but more doesn't turn on things more. (I.e. a switch not a dial).

The older you are the less sensitive your muscles are to being turned on for growth, thus slightly more leucine is required to switch on muscle growth signalling. (I.e. a teenager may require ~2g leucine, an older person ~4g leucine.)

Probably the least useful thing women (and men) could do as they age, in the context of holding onto muscle, strength, and movement ability, is to do less and less load-barring exercise, and to eat a low protein diet predominantly from plant sources.

I am not saying don't eat plant sources of protein, I am saying you should be eating more protein as you age, and even more if you only eat plant sources. Plus you should be doing muscle taxing exercise.

So in closing, I agree with the podcast host's guest that chronically stimulating cell growth is not helpful. But I do not agree that limiting leucine wholesale is beneficial.

In fact I think it's almost the opposite advice. We should be consuming foods rich in leucine within the right context. That is individual meals containing ~3g of leucine per meal at a minimum across the day in the context of exercise. Not just consuming low protein (<2g leucine) meals which are very common when eating an only plant-based diet.

Context is key!

We should be stimulating the body to grow and repair muscle, not doing everything we can to limit that.

As we age we want to remain active and able, and maximsing food quality along with exercise quality is the very best thing you can do.

Saying leucine is bad wholesale (i.e. animal products are bad) because it stimulates cell growth, is as naive as saying resistance exercise is bad because it stimulates cell growth.

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"Declines in muscle mass in older women may be attenuated with habitual twice-daily consumption of a protein beverage providing 15g protein and higher (4.2 g/serving) amounts of leucine."

on the contrary, it ameliorated several parameters related to physical performance"

"Bottom line: While you would expect athletes (or their performance) to suffer most from potential side effects of alternate day fasting, the study at hand shows that it's not the athletes' performance that suffers.

Rather than that, athletes should be concerned about potential nutrient deficiencies, which should be easy to solve by the means of a multi-vitamin+mineral supplement - not one of the mega-dosed bullshit products, but a basic one with 100% of the RDA.

With overall no effect on exercise performance and a significant increase in exercise efficacy, one may even argue that performance was, next to improvements in lipid metabolism (cholesterol and triglycerides were significantly lower after the six-week period), surprising increases in vitamin D (probably due to an overall reduction in oxidative damage | learn more), and of course, an overall improvement of body composition. The study at hand didn't find any reason why people who train up to four times a week couldn't use an alternate day fasting (ADF) routine to get shredded or resolve inflammation/bodyweight related health problems.

"If you just read the abstract it would seem like supplementing with bug protein had no body comp benefits....except the control group increased their protein intake over the course of the study to 1.7 g/kg.

What the study actually showed was that consuming 1.7 g/kg vs 2.3 g/kg resulted in similar increases in lean mass."

"cool study that confirms a lot of what we know both practically and theoretically.

pushups are a great closed chain exercise & can be loaded for progression with a partner or belt (get a couple benches so it can hang). chin tucked, brace the core, allow scapular movement across the rib cage.

the bench is just one of those die hard bro exercises. great exercise but all in all just a tool for our hypertrophy goals"

"If you have a chest (or leg, or back) "day" (where you do 3-4 exercises for chest) you'll no doubt get a great chest workout. BUT:

Unless you're insanely big and strong, you'll be fully recovered in about 2 days, maybe less. So then what? You'll need to do ANOTHER chest day, or you'll be losing ground. Presumably however, you've got other muscles to train as well, so when will that happen?

This is the problem with "bro splits." The VAST majority of people will be better off training "whole body" style roughly 3 days per week. Just use one exercise per muscle (or better yet — per pattern).

No, that won't hit the muscle "from every angle" so use different exercises on days two and three."